JPS627126B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for removing aluminum chloride from an aluminum chloride solution combined with liquid metal chloride resulting from the chlorination of titanium-containing materials, and more particularly, An improved process for removing aluminum chloride that substantially eliminates the loss of titanium tetrachloride, causes no substantial loss of ferrous chloride from solution, and reduces the formation of HCl. Titanium tetrachloride is rutile or ilmenite,
Alternatively, it is produced industrially by chlorinating titanium-containing materials under reductive conditions, such as other titanium-rich materials such as those obtained by enrichment of such ores. In addition to their titanium values, these raw materials contain varying amounts of other metals, especially iron and aluminum compounds. Following the conversion of titanium and other metals to volatile chlorides by chlorination, the chlorides are recovered and condensed to solid or liquid form, depending on the composition and the physical nature of the recovery equipment used. A liquid sludge is usually obtained which is undesirably contaminated with dissolved impurities and undissolved solid materials. The amount and type of chloride present in the crude product is
It depends on the exact composition of the titanium-containing raw material being chlorinated and the chlorination method used. However, the presence of aluminum chloride can be expected in virtually all cases where aluminum compounds are present in the raw materials or in the constituent materials of equipment, such as furnace bricks. The prior art has long recognized that aluminum chloride is a highly corrosive component in liquid metal chloride mixtures. Aluminum chloride rapidly and severely damages the metallic materials of the components in the processing equipment, so either it must be rapidly removed from the liquid or the equipment must be specially lined with ceramic to prevent corrosion. An early attempt to overcome this problem is described in US Pat. No. 2,600,881. This method is based on the discovery that water forms non-corrosive, insoluble aluminum compounds, thereby removing aluminum chloride from other metal chlorides resulting from chlorination reactions.
At the time of this discovery, using water in excess of the stoichiometric amount would cause the water to react with the desired titanium tetrachloride to form titanium oxychloride, leading to loss of titanium value in titanium-containing materials. considered undesirable for this reason. However, it has been found that in order to carry out this process on an industrial scale, at least a 10% excess of the stoichiometric amount of water is required to ensure complete aluminum chloride removal. Because it is virtually impossible to determine how much of the metal chloride present in the reaction vessel at any point in the chlorination process is actually aluminum chloride, thus ensuring complete removal. This is because a slight excess of water is required. This excess necessarily results in a corresponding loss of titanium value. Another method used to remove aluminum chloride from mixtures of aluminum chloride and metal chlorides, such as titanium tetrachloride, is described in U.S. Pat.
Listed in 3066010. This method involves contacting a gaseous mixture of metal chlorides containing aluminum chloride with a column of solid sodium chloride, whereby the sodium chloride is combined with the aluminum chloride and the solid ferric chloride also present in the gaseous mixture. including forming a complex of Although this method is useful if it is desired to recover only titanium tetrachloride from a gaseous mixture, if ferric chloride is present in more than a trace amount, its removal will reduce the consumption of NaCl. ferrous chloride and waste disposal problems, and in many cases it is desirable to retain ferrous chloride because of its economic value in areas such as water purification. The present invention is capable of completely removing the corrosive and undesirable aluminum chloride component in liquid chloride mixtures resulting from the chlorination of titanium-containing materials, while essentially eliminating the loss of titanium value in the mixture. provides a method for preserving the potentially valuable ferric chloride component and reducing HCl production. The present invention produces an insoluble aluminum compound by mixing a liquid metal chloride resulting from the chlorination of a titanium-containing material with a solution of solid aluminum chloride with water, and then separates the compound therefrom. An improved method for removing aluminum chloride from the solution is provided.
Modification to ensure complete separation of aluminum chloride from the solution without substantial loss of the titanium tetrachloride component of the solution involves mixing water and sodium chloride with the solution, The amount of water in the case is less than equimolar to the total amount of aluminum in the ore, and the total amount of water and sodium chloride is at least equimolar to the total amount of aluminum in the ore. The amount of water is at least 0.5 equimolar (half an equimolar amount) relative to the amount of aluminum in the ore, but less than 1.0 equimolar amount (equimolar amount), and the remainder up to the equimolar amount is sodium chloride. is suitable. Furthermore, it is preferable that sodium chloride is present in an amount that is at least 0.1 equimolar in excess of the total equimolar amount of sodium chloride and water relative to the amount of aluminum in the ore. In order to ensure complete removal of aluminum chloride, it is particularly preferred that the sodium chloride is in an equimolar excess of at least 0.2 over the combined equimolar amount of sodium chloride and water. In principle, there is no need to put an upper limit on the amount of sodium chloride used, but it should be in excess of no more than 0.5 equimole over the total equimolar amount of water and sodium chloride relative to the total amount of aluminum in the ore. It is recommended that it be used. The use of large quantities is not effective in further removing aluminum chloride and only increases waste disposal problems. If the amount of AlCl ₃ in the effluent varies by more than 20% by weight, there will be less water and more NaCl.
For example, it is recommended to use 0.7 equimolar water and 0.6 equimolar NaCl or 0.6 equimolar water and 0.8 equimolar NaCl. Sodium chloride and water can be added to the metal chloride liquid mixture at any time or separately. In order to ensure complete reaction of the sodium chloride with the aluminum chloride component of the liquid mixture, it is desirable that the sodium chloride be mixed with the liquid metal chloride mixture under at least suitable agitation conditions. To ensure a complete reaction,
More preferably, the sodium chloride has an average particle size of 30μ to 400μ. The present invention can be practiced with metal chloride mixtures originating from any titanium-containing material, including enriched ores containing greater than 90% titanium dioxide. However, the greatest advantages of the present invention are realized in low grade ores such as ilmenite containing more than 10% iron, calculated as iron oxide. The method of chlorinating the titanium-containing material to form a mixture of metal chlorides is not essential to the practice of the present invention. However, the resulting mixture of metal chlorides, especially when ferric chloride is a component of the mixture, must be substantially liquid for the effective practice of this invention. It has been found that in the gaseous state, ferric chloride reacts with sodium chloride at approximately the same rate as aluminum chloride, and both of these components are removed. However, in the liquid state, chloride
Iron is not as soluble in liquid titanium tetrachloride as aluminum chloride; therefore, in the liquid state, sodium chloride reacts preferentially with aluminum chloride under suitable agitation conditions, and ferric chloride reacts less favorably with titanium tetrachloride. It has been found that it remains and is removed therefrom at a later stage in the process. The manner in which the required amount of water is added to the metal chloride mixture is relatively unimportant as long as an intimate mixture is obtained. Water can be added to the liquid mixture as a liquid or stream by simply dropping or otherwise providing it onto the surface of the liquid mixture, or if desired, it can be injected into the liquid. If not, it can be mixed with the liquid by any known or desired means. Similarly, intimate mixtures can be prepared by using conventional means such as mechanical agitation by spatulas, circulation pumps or similar means. The time required to achieve proper mixing and processing appears to depend on the efficiency of the mixing operation rather than the rate of the chemical reaction, which has been found to be significantly faster. The sodium chloride additive can be mixed with the liquid mixture of metal chlorides as well, but unlike the water component, it must be mixed at least under suitable agitation conditions to ensure intimate contact with the metal chlorides. Must be mixed. Sodium chloride can be added alone as a solid or as a solution with an aqueous component. The temperature of the metal chloride mixture that is intimately mixed with water and sodium chloride must be low enough to ensure that the mixture is in substantially liquid form, i.e., at normal pressure
Below 136°C or under high pressure it must be adjusted accordingly. The amounts of water and sodium chloride used according to the aforementioned guidelines are calculated based on the total amount of aluminum chloride present in the metal chloride mixture. This amount of aluminum chloride is calculated based on the total amount of aluminum present in the titanium-containing material to be chlorinated. Although it was previously pointed out that at any given point in the process, the amount of aluminum chloride exiting the reactor will vary somewhat, using water and sodium chloride in accordance with the present invention based on the total amount present, at some point The need to know the exact amount of aluminum chloride present is avoided. This is because the amount of water used is less than the stoichiometric amount and therefore no loss of titanium values occurs. The sodium chloride used reacts selectively with aluminum chloride leaving titanium tetrachloride, which is later recovered. The following examples are intended to illustrate the invention. Example 1 and Comparative Example In order to determine the corrosion rate of steel metal samples in a simulated liquid TiCl ₄ effluent, a corrosive liquid having the composition detailed in the table was prepared in the following manner. : Obtained as a commercial product
200 ml of _TiCl4 was redistilled to ensure the removal of traces of _TiOCl2 . The redistilled TiCl ₄ was placed in an external distillation vessel equipped with a conventional agitator or propeller and associated condensation means. The liquid was stirred by a propeller at a speed of 450 rpm and nitrogen was flushed throughout the test. Liquid water was added using a syringe.
Dry NaCl with a particle size of -200 + 325 mesh (US standard sieve) was then added. After heating the resulting mixture to a boiling point of about 136° C., 9.0 g of commercially available anhydrous AlCl ₃ were added. Two identical 1020 steel coupons were then immediately added. The steel tag and all surfaces contacted by the liquid TiCl ₄ were carefully dried by heating in a nitrogen atmosphere before use. After being immersed in the liquid mixture for 1 hour, the steel tags were removed from the liquid mixture, washed with water and acetone, dried in a desiccator, and weighed. The corrosion rate in mils/month was calculated by the following formula: Corrosion rate (mils/month) = 283 × weight loss of tag (mg/hr) / area of tag (cm ² ) × specific gravity of tag As shown in the table, Example 1 showed negligible corrosion and Ta. Comparative Example 1-A, which contained no anti-corrosion additives, showed very high corrosion.
Comparative Example 1-B using only NaCl showed some reduction in corrosion, but the corrosion rate was still unacceptably high. Although water-only Comparative Example 1-C further reduced corrosion, it cannot be used in large enough quantities without incurring loss of TiCl ₄ . Example 2.2R and Comparative Example The procedure of Example 1 was followed except that 32.4 g of sublimed anhydrous FelCl ₃ was added to the liquid mixture and then heated to boiling point. _FeCl3 during heating
To prevent it from reacting with NaCl, NaCl is replaced by AlCl ₃
and added just before adding the steel tag. The composition and corrosion rate of this test liquid mixture are shown in the table. Example 3 The procedure of Example 1 was followed except that 18.0 g of AlCl ₃ was added to the reaction vessel, heated to 100° C., 3.94 g of NaCl was added, and then 1.70 g of H ₂ O was added. . The amount of NaCl was 0.5 equimole relative to AlCl ₃ and the amount of H ₂ O was 0.7 equimole relative to AlCl ₃ . The resulting mixture was heated to the boiling point, 136° C., and refluxed for 1 hour. Then the mixture TiCl ₄
The components were distilled off leaving 14.7 g of solid residue. Analysis of the solid residue revealed only small amounts of titanium,
Specifically, it was found to contain 0.44% titanium by weight and essentially all of the aluminum initially added to the mixture. This analysis shows that substantially all of the TiCl ₄ in the initial mixture was recovered. 【table】

Claims (1)

[Claims] 1. To remove aluminum chloride from a solution of aluminum chloride and a liquid mixture of metal chlorides resulting from chlorination of a titanium-containing material, water is mixed into the liquid mixture to remove aluminum. water and sodium chloride are mixed with the liquid mixture, the amount of water being equal to the total amount of aluminum in the ore, and separating the insoluble compound from the system. However, the total amount of water and sodium chloride should be at least equimolar to the total amount of aluminum in the ore, thereby essentially causing a loss of the titanium tetrachloride component in the liquid mixture. The method is characterized in that it is possible to completely separate aluminum chloride. 2. The method according to claim 1, wherein the amount of sodium chloride is at least 0.1 equimolar excess of the total equimolar amount of water and sodium chloride relative to the total amount of aluminum in the ore.